Extracorporeal blood treatment method

ABSTRACT

An extracorporeal blood treatment apparatus comprises: a blood treatment device ( 2 ) comprising a blood chamber ( 3 ) and a fluid chamber ( 4 ) separated from one another by a semipermeable membrane ( 5 ); an extracorporeal blood circuit ( 17 ) comprising a blood withdrawal line ( 6 ) connected to an inlet port ( 3   a ) of the blood chamber ( 3 ) and a blood return line ( 7 ) connected to an outlet port ( 3   b ) of the blood chamber ( 3 ); a blood pump ( 21 ) configured to be coupled to the blood withdrawal line ( 6 ); a hydraulic circuit ( 100 ) connectable to the fluid chamber ( 4 ), wherein the hydraulic circuit ( 100 ) comprises a fluid preparation device ( 9 ) connected to a water network ( 14 ) and configured to dilute concentrates in water to prepare a treatment fluid; a control unit ( 12 ) connected to the preparation device ( 9 ) and to the blood pump ( 21 ). The control unit ( 12 ) is configured to execute the following procedure: setting the hydraulic circuit ( 100 ) so that the fluid preparation device ( 9 ) bypasses the fluid chamber ( 4 ); controlling the fluid preparation device ( 9 ) to prepare the treatment fluid while bypassing the fluid chamber ( 4 ); and simultaneously controlling the blood pump ( 21 ) to perform pure ultrafiltration of a patient (P) connected to the extracorporeal blood circuit ( 17 ).

PRIORITY CLAIM

The present application is continuation of U.S. Ser. No. 16/956,958,filed Jun. 22, 2020, entitled “Extracorporeal Blood TreatmentApparatus”, which is a National Phase of International Application No.PCT/EP2018/068214, filed Jul. 5, 2018, which claims priority to EPApplication No. 17210994.4, filed Dec. 28, 2017, the entire contents ofeach of which are incorporated herein by reference and relied upon.

DESCRIPTION Field of the Invention

The present invention relates to an extracorporeal blood treatmentapparatus. The extracorporeal blood treatment apparatus according to theinvention is of the kind that could comprise a device for on-linepreparation of a treatment fluid. The described embodiment also concernsa method for controlling an extracorporeal blood treatment apparatus.

Extracorporeal blood treatment involves removing blood from a patient,treating the blood externally to the patient, and returning the treatedblood to the patient. Extracorporeal blood treatment is typically usedto extract undesirable matter or molecules from the patient's bloodand/or to add desirable matter or molecules to the blood. Extracorporealblood treatment is used with patients unable to effectively removematter from their blood, such as when a patient has suffered temporaryor permanent kidney failure. These patients and other patients mayundergo extracorporeal blood treatment to add or remove matter to theirblood, to maintain an acid/base balance or to remove excess body fluids,for example.

Extracorporeal blood treatment is typically accomplished by removing theblood from the patient in e.g. a continuous flow, introducing the bloodinto a primary chamber, also referred to as blood chamber, of atreatment unit (such as a dialyzer or an hemo-filter) where the blood isallowed to flow past a semi-permeable membrane. The semi-permeablemembrane selectively allows matter in the blood to cross the membranefrom the primary chamber into a secondary chamber and also selectivelyallows matter in the secondary chamber to cross the membrane into theblood in the primary chamber, depending on the type of treatment.

A number of different types of extracorporeal blood treatments may beperformed. In an ultrafiltration (UF) treatment, undesirable fluid isremoved from the blood by convection across the membrane into thesecondary chamber. In a hemofiltration (HF) treatment, the blood flowspast the semipermeable membrane as in UF (where waste and undesirablefluid are removed) and desirable matter is added to the blood, typicallyby dispensing a fluid into the blood either before and/or after itpasses through the treatment unit and before it is returned to thepatient. In a hemodialysis (HD) treatment, a secondary fluid containingdesirable matter is introduced into the secondary chamber of thetreatment unit. Undesirable matter from the blood crosses thesemipermeable membrane into the secondary fluid by diffusion anddesirable matter from the secondary fluid crosses the membrane into theblood. In a hemodiafiltration (HDF) treatment, blood and secondary fluidexchange matter as in HD, and, in addition, matter is added to theblood, typically by dispensing a fluid into the treated blood (infusion)either before and/or after it passes through the treatment unit andbefore its return to the patient as in HF.

In order to perform extracorporeal blood treatment therapies involvingthe use of treatment fluid prepared by the device for on-linepreparation of a treatment fluid, the device must be switched on andparameters of the treatment fluid (like conductivity, temperature andflow rate) must be adjusted before starting the treatment.

Background

Document WO2015184033A2 discloses a method for treating dialysatesolutions used in sorbent dialysis wherein a small volume of dialysateis continuously regenerated. To initially prepare dialysate forcirculation through dialysate circuit, the dialysate circuit is primedwith a precursor dialysate solution in a supply container. Aftercompleting the introduction of the precursor dialysate solution into thedialysate circuit, valves are opened so that dialysate can flow betweenthe dialyzer and the dialysate circuit concurrent with blood flow fromand to the patient through the dialyzer to support a dialysis treatment.Dialysate is made in-situ. A supply of saline in the form of a salinebag is used to prime the blood circuit. Sterile saline can also be usedto prime the dialysate circuit.

Document U.S. Pat. No. 4,718,022A discloses a dialysis machine having acontrol circuit which detects changes in input water temperature andcompensates the water heater. The dialysis machine proceeds to producedialysate during the priming operation of hydraulic circuit. In thepriming mode, however, the dialysate being produced is either internallyor externally recirculated so as to bypass the artificial kidney. Oncethe dialysis machine determines that the dialysate is being produced atthe selected temperature, flow rate and pressure, the operator may benotified that dialysis may be commenced. Priming of blood circuit withsaline is also performed.

Document WO9625214A1 discloses a machine for conducting dialysis of bodyfluids of a patient which is suitable for use in home environment. Thisdocument discloses to prepare dialysate in a tank of a dialysispreparation module, to check the integrity of the dialysate circuit andto prime the extracorporeal blood circuit. Water is back-filtered acrossthe membrane of the dialyzer into the extracorporeal circuit. Theautomatic priming process may be implemented as a sequence of stepspre-, during, and post-dialysate preparation. Priming of theextracorporeal circuit with saline is also disclosed.

Document WO0006217A1 discloses an apparatus and method for controllingultrafiltration and a method for priming blood compartment of ahemodialyzer. WO0006217A1 discloses to produce on-line a dialysatesolution in the hydraulic circuit by mixing concentrates in a waterstream. Before beginning a dialysis treatment, dialysate flow by-passthe hemodialyzer flowing through rinse block. Priming of blood lines andcompartment is achieved by urging passage of dialysate from thedialysate compartment to the blood compartment and thus eliminates theneed to consume isotonic saline.

Known apparatuses and methods as described above require time to performdialysis on-line fluid preparation. Specifically though not exclusively,fluid preparation in extracorporeal blood treatment machines for ICHDtreatments (In Center Haemo-Dialysis) is critical.

When a patient reaches the clinic with excessive fluid to be removedurgently, he has to wait for on-line fluid preparation and for primingof the circuits before starting the treatment. Indeed, only oncedialysis fluid is at the proper conductivity and temperature, the bloodcircuit can be primed. This implies tens of minutes to start any fluidremoval from patient and/or treatment and this causes patient discomfortand pain and stress for the clinic staff because of the emergencysituation.

SUMMARY OF THE INVENTION

In view of the above, it is an object of the present invention toprovide an extracorporeal blood treatment apparatus and method ofcontrolling an extracorporeal blood treatment apparatus which are ableto obviate at least some of the described drawbacks of the prior art.

It is a further object of the present invention to provide an apparatusand a method which are able to shorten the waiting time (time totreatment) for the patient.

It is a further object of embodiments of the present invention toprovide an apparatus and a method which are able to reduce the physicalstress of the patients.

It is a further object of embodiments of the present invention toprovide an apparatus and a method which are able to provide a bettertreatment to patients, in particular though not exclusively, to patientsin severe or critical conditions.

It is a further object of embodiments of the present invention toprovide an apparatus and a method which are able to increase the therapyoffer of the clinic (number of treated patients per time unit).

It is a further object of embodiments of the present invention toprovide an apparatus and a method which are able to optimize theefficiency of the clinic and the exploitation of available apparatusesfor extracorporeal treatment of blood.

At least one of the above objects is substantially achieved byperforming online preparation of the treatment fluid simultaneously withpure ultrafiltration of the patient, and optionally with priming, whilethe blood treatment device is in by-pass, then starting dialysis whenthe treatment fluid is ready. Pure ultrafiltration means ultrafiltrationwithout simultaneous dialysis (fluid removal only in the blood treatmentdevice and no hemodialysis or hemofiltration).

Aspects of the invention are disclosed in the following.

In accordance with a 1^(st) independent aspect, an extracorporeal bloodtreatment apparatus comprises:

a blood treatment device comprising a blood chamber and a fluid chamberseparated from one another by a semipermeable membrane;

an extracorporeal blood circuit comprising a blood withdrawal lineconnected to an inlet port of the blood chamber and a blood return lineconnected to an outlet port of the blood chamber;

a blood pump configured to be coupled to the extracorporeal bloodcircuit to circulate blood in the extracorporeal blood circuit, inparticular configured to be coupled to the blood withdrawal line;

a hydraulic circuit including a main line connectable to an inlet portof the fluid chamber and/or to the extracorporeal blood circuit and aneffluent line connected to an outlet port of the fluid chamber, the mainline being connectable to a water network to receive water, wherein thehydraulic circuit comprises a fluid preparation device configured todilute concentrates in water flowing in the main line to prepare atreatment fluid having set conductivity and/or set ion concentration;

an ultrafiltration device to ultrafilter liquid from the blood chambertowards the fluid chamber of the blood treatment device and to theeffluent line;

a control unit connected to the preparation device, to theultrafiltration device and to the blood pump;

wherein the control unit is configured to execute the followingprocedure:

setting the hydraulic circuit so that a fluid prepared through the fluidpreparation device and not having the set conductivity and/or the setion concentration bypasses the fluid chamber and is not infused in theextracorporeal blood circuit;

controlling the fluid preparation device to change a conductivity and/oran ion concentration of the fluid not having the set conductivity and/orthe set ion concentration to prepare the treatment fluid having the setconductivity and/or the set ion concentration while bypassing the fluidchamber and not infusing the fluid in the extracorporeal blood circuit;and

simultaneously controlling the ultrafiltration device to perform pureultrafiltration of fluid from the extracorporeal blood of a patientconnected to the extracorporeal blood circuit.

In accordance with a 2^(nd) independent aspect, a method for controllingan extracorporeal blood treatment apparatus, particularly of the type inaccordance with the 1^(st) aspect, comprises:

setting a hydraulic circuit so that a fluid prepared through a fluidpreparation device and not having a set conductivity and/or a set ionconcentration bypasses a fluid chamber of a blood treatment device andis not infused in the extracorporeal blood circuit;

controlling the fluid preparation device to change a conductivity and/oran ion concentration of the fluid not having the set conductivity and/orthe set ion concentration to prepare the treatment fluid having the setconductivity and/or the set ion concentration while bypassing the fluidchamber and not infusing the fluid in the extracorporeal blood circuit;and

simultaneously controlling an ultrafiltration device of theextracorporeal blood treatment apparatus to perform pure ultrafiltrationof fluid from the extracorporeal blood of a patient connected to theblood withdrawal line and to a blood return line of an extracorporealblood circuit.

In accordance with a further independent aspect, an extracorporeal bloodtreatment apparatus is provided comprising:

a blood treatment device comprising a blood chamber and a fluid chamberseparated from one another by a semipermeable membrane;

an extracorporeal blood circuit comprising a blood withdrawal lineconnected to an inlet port of the blood chamber and a blood return lineconnected to an outlet port of the blood chamber;

a blood pump configured to be coupled to the extracorporeal bloodcircuit to circulate blood in the extracorporeal blood circuit, inparticular configured to be coupled to the blood withdrawal line;

a hydraulic circuit including a main line connectable to an inlet portof the fluid chamber and/or to the extracorporeal blood circuit and aneffluent line connected to an outlet port of the fluid chamber, the mainline being connectable to a water network to receive water, wherein thehydraulic circuit comprises a fluid preparation device configured todilute concentrates in water flowing in the main line to prepare atreatment fluid having set conductivity and/or set ion concentration;

an ultrafiltration device to ultrafilter liquid from the blood chambertowards the fluid chamber of the blood treatment device and to theeffluent line;

at least one priming fluid, e.g. saline, reservoir connected to theextracorporeal blood circuit or to the blood treatment device or to thehydraulic circuit;

a control unit connected to the preparation device, to theultrafiltration device and to the blood pump;

wherein the control unit is configured to execute the followingprocedure:

setting the hydraulic circuit so that a fluid prepared through the fluidpreparation device and not having the set conductivity and/or the setion concentration bypasses the fluid chamber and is not infused in theextracorporeal blood circuit;

controlling the fluid preparation device to change a conductivity and/oran ion concentration of the fluid not having the set conductivity and/orthe set ion concentration to prepare the treatment fluid having the setconductivity and/or the set ion concentration while bypassing the fluidchamber and not infusing the fluid in the extracorporeal blood circuit;and simultaneously, in a priming configuration, priming theextracorporeal blood circuit with a priming fluid before connecting thepatient and while the fluid preparation device is preparing thetreatment fluid.

In a 3^(rd) aspect according to any of the previous aspects, in apriming configuration, the apparatus comprises at least one primingfluid, e.g. saline, source, e.g. a reservoir, connected to theextracorporeal blood circuit or to the blood treatment device or to thehydraulic circuit.

In a 4^(th) aspect according any of the previous aspects, the controlunit is configured to execute the following procedure or the methodcomprises: in a priming configuration, priming the extracorporeal bloodcircuit with a priming fluid before connecting the patient and while thefluid preparation device is preparing the treatment fluid, in particularthe priming fluid source being connected to the extracorporeal bloodcircuit.

In a 5^(th) aspect according to any the previous aspect 3 or 4, thecontrol unit is configured to execute the following procedure or themethod comprises: in a priming configuration, priming the fluid chamberand optionally at least part of the hydraulic circuit with the primingfluid by pushing the priming fluid through the membrane from the bloodchamber into the fluid chamber before connecting the patient and whilethe fluid preparation device is preparing the treatment fluid.

In an alternative 5^(th) aspect according to any the previous aspect 3or 4, the control unit is configured to execute the following procedureor the method comprises: in a priming configuration, priming the fluidchamber and optionally at least part of the hydraulic circuit with apriming fluid from an auxiliary priming fluid source, e.g. a container,the auxiliary priming fluid source being connected to the bloodtreatment device or to the hydraulic circuit and being separated by thesemipermeable membrane from the extracorporeal blood circuit.Optionally, the auxiliary priming fluid source being connected via atubing directly to the inlet port of the fluid chamber.

In a 6^(th) aspect according to any of the previous aspects from 1 to 5,the control unit is configured to execute the following procedure or themethod comprises: in a treatment configuration, connecting the fluidpreparation device to the fluid chamber and/or to the extracorporealblood circuit when the treatment fluid having the set conductivityand/or the set ion concentration is ready for treating the patientblood.

In a 7^(th) aspect according to any of the previous aspects from 1 to 6,the control unit is configured to execute the following procedure or themethod comprises: in a treatment configuration, starting a hemodialysistreatment or a hemofiltration treatment or a hemodiafiltration treatmenton the patient when the treatment fluid having the set conductivityand/or the set ion concentration is ready.

In an 8^(th) aspect according to any of the previous aspects from 1 to7, the main line of the hydraulic circuit comprises a valve operativelyplaced between the preparation device and the inlet port of the fluidchamber.

In a 9^(th) aspect according to the previous aspect 8, the control unitis connected to the valve and is configured to execute the followingprocedure: in a treatment fluid preparation configuration, closing thevalve to set the fluid flowing in the main line downstream the fluidpreparation device to bypass the fluid chamber.

In a 10^(th) aspect according to the previous aspect 4, in the primingconfiguration, priming the extracorporeal blood circuit includescontrolling the blood pump while the priming fluid source is connectedto the extracorporeal blood circuit to pump the priming fluid in theextracorporeal blood circuit and to prime the extracorporeal bloodcircuit with the priming fluid.

Optionally, in the priming configuration the extracorporeal bloodcircuit is directly connected to the fluid chamber through a tubing.Optionally, the blood withdrawal line is directly connected to the fluidchamber, optionally to the inlet port of the fluid chamber. Optionally,the blood pump circulates the priming fluid along a reverse circulatingdirection. The blood pump pumps the priming fluid into the fluid chamberthrough the tubing, in order to prime said fluid chamber and optionallyat least part of the hydraulic circuit. Optionally, in the primingconfiguration, the priming fluid flows through the blood chamber, out ofthe inlet port of the blood chamber and then into the fluid chamber.Optionally, the priming fluid exits from the outlet of the fluid chamberand flows into the effluent line.

In an 11^(th) aspect according to any of the previous aspects 3, 4 or10, the apparatus comprises a safety valve placed on the blood returnline, the control unit being connected to the safety valve, and anarterial clamp placed on the blood withdrawal line, the control unitbeing connected to the arterial clamp.

In a 12^(th) aspect according to the previous aspect 11, in the primingconfiguration, priming the extracorporeal blood circuit includes a firstphase of priming the blood withdrawal line and the blood return lineactivating the blood pump to circulate priming fluid along a reversecirculating direction, in the extracorporeal blood circuit and keepingthe arterial clamp and the safety valve open and a second, optionallysubsequent, phase of closing the safety valve and activating the bloodpump to circulate the priming fluid in the blood circuit along a normalcirculating direction, thereby pushing the priming fluid through themembrane and priming the fluid chamber with the priming fluid.

In a 13^(th) aspect according to the previous aspect 12, the apparatuscomprises a drain in fluid communication with the fluid chamber and thesecond phase includes removing air from the fluid chamber through thedrain.

In a 14^(th) aspect according to any of the previous aspects 8 or 9, thecontrol unit is configured to execute the following procedure: in atreatment configuration, when the treatment fluid is ready in order tostart a hemodialysis treatment or a hemofiltration treatment or ahemodiafiltration treatment on the patient, opening the valve to connectthe fluid preparation device to the inlet port of the fluid chamberand/or to an infusion line for injecting substitution fluid in the bloodcircuit.

In a 15^(th) aspect according to any of the previous aspects 1 to 14, atime interval for treatment fluid preparation is comprised between 15min and 30 min.

In a 16^(th) aspect according to any of the previous aspects from 1 to15, a time interval for pure ultrafiltration is comprised between 10 minand 20 min.

In a 17^(th) aspect according to any of the previous aspects 4, 5 or 6to 16 when referring to aspect 4 or 5, a time interval for priming iscomprised between 5 min and 10 min.

In a 18^(th) aspect according to any of the previous aspects 1 to 17, atime to treatment from the start of the treatment fluid preparation tostart the pure ultrafiltration is less than 10 min, optionally less than5 min.

In a 19^(th) aspect according to any of the previous aspects 1 to 18,the priming fluid is saline, in particular saline including asubstantially isotonic liquid with no potassium and magnesium ions.

In a 20^(th) aspect according to any of the previous aspects form 1 to19, the treatment fluid comprises dialysis liquid including treatmentamounts of at least sodium, magnesium and potassium.

In a 21^(st) aspect according to any of the previous aspects from 1 to20, concentrates comprises sodium chloride and/or calcium chlorideand/or magnesium chloride and/or potassium chloride and/or bicarbonate.

In a 22^(nd) aspect according to any of the previous aspects from 1 to21, the fluid chamber comprises an inlet port and an outlet port,wherein the hydraulic circuit is connected to the inlet port and theoutlet port of the fluid chamber.

In a 23^(rd) aspect according to any of the previous aspects from 1 to22, the fluid preparation device is connected to the inlet port of thefluid chamber.

In a 24^(th) aspect according to any of the previous aspects from 1 to23, an effluent line for waste fluid is connected to the outlet port ofthe fluid chamber.

In a 25^(th) aspect according to any of the previous aspects from 1 to24, an arterial clamp is placed on the blood withdrawal line.

In a 26^(th) aspect according to any of the previous aspects from 1 to25, the fluid preparation device comprises:

-   -   at least a first and a second concentrate sources,    -   a first and a second delivery lines for respectively connecting        the first and a second concentrate sources to the main line; and        a first and a second concentrate pumps configured to        respectively act on the first and a second delivery lines to        allow the metered mixing of water and concentrated solution in        the main line.

In a 27^(th) aspect according to any of the previous aspects from 1 to26, the fluid preparation device comprises a conductivity or a ionconcentration sensor placed in the main line arranged to senseconductivity or ion concentration of the treatment fluid downstream aconcentrate dilution point, the control unit being connected to theconductivity or ion concentration sensor to receive a signal indicativeof the conductivity or ion concentration of the fluid flowing in themain line.

In a 28^(th) aspect according to the previous aspect, in the controllingof the fluid preparation device, the control unit is configured to:

-   -   receive, e.g. as input from an operator or from a memory, the        set conductivity and/or the set ion concentration for the        treatment fluid;    -   start injecting at least one concentrated solution in the main        line to increase the conductivity or ion concentration of water        flowing in the main line.

In a 29^(th) aspect according to the previous aspect, in the controllingof the fluid preparation device, the control unit is further configuredto:

-   -   check, by means of the conductivity or ion concentration sensor,        whether the conductivity or ion concentration of the fluid        flowing in the main line has a proper value for treatment of        patient blood, a proper value being a value within a range        around the set conductivity and/or the set ion concentration for        the treatment fluid.

In a 30^(th) aspect according to the previous aspect, the range aroundthe set conductivity and/or the set ion concentration for the treatmentfluid being less than +/−2 mS/cm, in particular less than +/−1 mS/cm,even more in particular less than 0.5 mS/cm.

In a 31^(st) aspect according to any of the previous aspects from 1 to30, the fluid preparation device comprises a temperature sensor placedin the main line arranged to sense the temperature of the treatmentfluid optionally downstream a concentrate dilution point, the controlunit being connected to the temperature sensor to receive a signalindicative of the temperature of the fluid flowing in the main line.

In a 32^(nd) aspect according to the previous aspect, in the controllingof the fluid preparation device, the control unit is configured to:

-   -   receive, e.g. as input from an operator or from a memory, the        set temperature for the treatment fluid;    -   start heating water and/or the fluid flowing in the main line.

In a 33^(rd) aspect according to the previous aspect, in the controllingof the fluid preparation device, the control unit is further configuredto:

-   -   check, by means of the temperature sensor, whether the        temperature of the fluid flowing in the main line has a proper        value for treatment of patient blood, a proper value being a        value within a range around the set temperature for the        treatment fluid.

In a 34^(th) aspect according to the previous aspect, the range aroundthe set temperature for the treatment fluid being less than +/−2° C., inparticular less than +/−1° C., even more in particular less than 0.5° C.

In a 35^(th) aspect according to any of the previous aspects from 1 to34, in a treatment fluid preparation configuration, the control unit isconfigured to execute the procedure of setting the hydraulic circuit sothat the fluid prepared through the fluid preparation device and nothaving the set conductivity and/or the set ion concentration bypassesthe fluid chamber and is not infused in the extracorporeal bloodcircuit; and controlling the fluid preparation device to change aconductivity and/or an ion concentration of the fluid not having the setconductivity and/or the set ion concentration to prepare the treatmentfluid having the set conductivity and/or the set ion concentration whilebypassing the fluid chamber and not infusing the fluid in theextracorporeal blood circuit, wherein controlling the fluid preparationdevice includes start injecting at least one concentrate solution inwater to rise water conductivity and/or ion concentration.

In a 36^(th) aspect according to any of the previous aspects from 1 to35, in a pure UF configuration, the control unit is configured toexecute the procedure of setting the hydraulic circuit so that the fluidprepared through the fluid preparation device bypasses the fluid chamberand is not infused in the extracorporeal blood circuit; and controllingthe ultrafiltration device to perform pure ultrafiltration of fluid fromthe extracorporeal blood of a patient connected to the extracorporealblood circuit.

In a 37^(th) aspect according to previous aspects 35 and 36, at least atthe starting of the apparatus, the apparatus is configured (or thecontrol unit configures the apparatus) simultaneously in the treatmentfluid preparation configuration and in the pure UF configuration.

In a 38^(th) aspect according to previous aspects 4 and 37, at least atthe starting of the apparatus, the apparatus is configured (or thecontrol unit configures the apparatus) simultaneously in the treatmentfluid preparation configuration and in the priming configuration.

In a 39^(th) aspect according to previous aspects 37 and 38, at least atthe starting of the apparatus, the apparatus is configured (or thecontrol unit configures the apparatus) simultaneously in the treatmentfluid preparation configuration and in the priming configuration andthereafter, once priming is ended, the apparatus is switched to beconfigured (or the control unit configures the apparatus to be)simultaneously in the treatment fluid preparation configuration and inthe pure UF configuration.

In a 40^(th) aspect according to any of the previous aspects from 1 to39, controlling the fluid preparation device to change a conductivityand/or an ion concentration of the fluid not having the set conductivityand/or the set ion concentration to prepare the treatment fluidcomprises controlling the fluid preparation device to substantiallycontinuously raising the conductivity and/or ion concentration of thefluid not having the set conductivity and/or the set ion concentrationup to obtaining a fluid substantially having the set conductivity and/orthe set ion concentration.

In a 41^(st) aspect according to previous aspect 40, controlling thefluid preparation device to substantially continuously raising theconductivity and/or ion concentration includes starting and thencontinuing injecting into water a concentrate ion solution.

In a 42^(nd) aspect according to any of the previous aspects, theapparatus comprises a fresh dialysis fluid container connected to theinlet port of the fluid chamber, the control unit being configured toadditionally run an hemodyalisis treatment flowing fresh dialysis fluidin the fluid chamber and patient blood in the blood chambersimultaneously with the step of controlling the fluid preparation deviceto change a conductivity and/or an ion concentration of the fluid nothaving the set conductivity and/or the set ion concentration to preparethe treatment fluid having the set conductivity and/or the set ionconcentration.

In a 43^(rd) aspect according to any of the previous aspects, theapparatus comprises a fresh dialysis fluid container connected to theextracorporeal blood circuit, the control unit being configured toadditionally run a hemofiltration treatment injecting fresh dialysisfluid in the extracorporeal blood simultaneously with the step ofcontrolling the fluid preparation device to change a conductivity and/oran ion concentration of the fluid not having the set conductivity and/orthe set ion concentration to prepare the treatment fluid having the setconductivity and/or the set ion concentration.

In a 44^(th) aspect according to any of the previous aspects, connectingthe patient after priming comprises: connecting the blood withdrawalline and the blood return line to the patient while an arterial clamp onthe blood withdrawal line and a safety valve on the blood return lineare closed; opening the arterial clamp and the safety valve andactivating the blood pump according to the normal circulating direction,to progressively substituting the priming fluid in the line with blood.

In a 45^(th) according to any of the previous aspects from 1 to 43^(rd),connecting the patient after priming comprises: connecting the bloodwithdrawal line to the patient while the blood return line is stillconnected to a priming fluid reservoir and an arterial clamp on theblood withdrawal line and a safety valve on the blood return line areclosed; opening the arterial clamp and the safety valve and activatingthe blood pump according to the normal circulating direction, toprogressively substituting the priming fluid in the line with blood andto collect the priming fluid in the priming fluid reservoir.

DESCRIPTION OF THE DRAWINGS

The following drawings relating to aspects of the invention are providedby way of non-limiting example:

FIG. 1 represents an extracorporeal blood treatment apparatus madeaccording to an illustrating embodiment;

FIGS. 2 to 5 show a schematic representation of the extracorporeal bloodtreatment apparatus of FIG. 1 in respective working conditions;

FIGS. 6 and 7 show a schematic representation of the extracorporealblood treatment apparatus of FIG. 1 in a different priming sequenceaccording to the invention;

FIG. 7A shows a schematic representation of the extracorporeal bloodtreatment apparatus of FIG. 1 in a further priming configurationaccording to the invention;

FIG. 7B shows a schematic representation of the extracorporeal bloodtreatment apparatus of FIG. 1 in a further priming configurationaccording to the invention;

FIGS. 8A and 8B show the connection of a patient to the extracorporealblood treatment apparatus after priming;

FIGS. 9A and 9B show another way of connecting a patient after priming;

and

FIG. 10 is a flowchart of the method of the invention implemented by theapparatus of the invention.

DETAILED DESCRIPTION

With reference to the appended drawings, FIG. 1 shows a schematicrepresentation of an extracorporeal blood treatment apparatus 1.

The apparatus 1 comprises one blood treatment device 2, for example ahemofilter, a hemodiafilter, a plasmafilter, a dialysis filter or otherunit suitable for processing the blood taken from a vascular access of apatient P.

The blood treatment device 2 has a first compartment or blood chamber 3and a second compartment or fluid chamber 4 separated from one anotherby a semipermeable membrane 5, for example of the hollow-fiber type orplate type. A blood withdrawal line 6 is connected to an inlet port 3 aof the blood chamber 3 and is configured, in an operative condition ofconnection to the patient P, to remove blood from a vascular accessdevice inserted, for example in a fistula on the patient P. A bloodreturn line 7 connected to an outlet port 3 b of the blood chamber 3 isconfigured to receive treated blood from the treatment unit 2 and toreturn the treated blood, e.g. to a further vascular access alsoconnected to the fistula of the patient P. Note that variousconfigurations for the vascular access device may be envisaged: forexample, typical access devices include a needle or catheter insertedinto a vascular access which may be a fistula, a graft or a central(e.g. jugular vein) or peripheral vein (femoral vein) and so on. Theblood withdrawal line 6 and the blood return line 7 are part of anextracorporeal blood circuit 17 of the apparatus 1.

The extracorporeal blood circuit 17 and the blood treatment device 2 areusually disposable parts which are loaded onto a frame of a bloodtreatment machine, not shown.

The blood circuit 17 may also comprise one or more air separators 19: inthe example of FIG. 1 a separator 19 is included at the blood returnline 7, upstream of a safety valve 20. Of course other air separatorsmay be present in the blood circuit 17, such as positioned along theblood withdrawal line 6. The safety valve 20 may be activated to closethe blood return line 7 when, for example, for security reasons theblood return to the vascular access has to be halted.

As shown in FIG. 1 , the apparatus 1 comprises at least a firstactuator, in the present example a blood pump 21, which is part of saidmachine and operates at the blood withdrawal line 6, to cause movementof the blood removed from the patient P from a first end of thewithdrawal line 6 connected to the patient P to the blood chamber 3. Theblood pump 21 is, for example, positive displacement pump like aperistaltic pump, as shown in FIG. 1 , which acts on a respective pumpsection of the withdrawal line 6. When rotated, e.g., clockwise, theblood pump 21 causes a flow of blood along the blood withdrawal line 6towards the blood chamber 3 (see the arrows in FIG. 1 indicative of theblood flow along the withdrawal line 6).

It should be noted that for the purposes of the present description andthe appended claims, the terms “upstream” and “downstream” may be usedwith reference to the relative positions taken by components belongingto or operating on the extracorporeal blood circuit. These terms are tobe understood with reference to a blood flow direction from the firstend of the blood withdrawal line 6 connected to the patient P towardsthe blood chamber 3 and then from the blood chamber 3 towards a secondend of the blood return line 7 connected to the vascular access of thepatient P.

The apparatus 1 further comprises a hydraulic circuit 100 cooperatingwith a blood circuit 17.

The hydraulic circuit 100 comprises a treatment fluid circuit 32presenting at least one treatment fluid supply line 8, destined totransport a treatment fluid from at least one source towards the bloodtreatment device 2.

The treatment fluid circuit 32 further comprises at least one effluentline 13, destined for the transport of a dialysate liquid or waste fluid(spent treatment fluid and liquid ultrafiltered from the blood through asemipermeable membrane 5) from the blood treatment device 2 towards anevacuation zone, schematically denoted by 16 in FIG. 1 .

The fluid supply line 8 is connected to an inlet port 4 a of the fluidchamber 4. The effluent line 13 is connected to an outlet port 4 b ofthe fluid chamber 4. The secondary chamber 4 is therefore connected tothe hydraulic circuit 100.

The apparatus of above-described embodiment may also comprise a userinterface 22 (e.g. a graphic user interface or GUI) and a control unit12, i.e. a programmed/programmable control unit, connected to the userinterface.

The control unit 12 may, for example, comprise one or more digitalmicroprocessor units or one or more analog units or other combinationsof analog units and digital units. Relating by way of example to amicroprocessor unit, once the unit has performed a special program (forexample a program coming from outside or directly integrated on themicroprocessor card), the unit is programmed, defining a plurality offunctional blocks which constitute means each designed to performrespective operations as better described in the following description.

In combination with one or more of the above characteristics, theextracorporeal blood treatment apparatus 1 may also comprise a closingdevice operating, for example, in the blood circuit 17 and/or in thetreatment fluid circuit 32 and controllable between one first operatingcondition, in which the closing device allows a liquid to flow towardsthe blood treatment device 2, and a second operative position, in whichthe closing device blocks the passage of liquid towards the bloodtreatment device 2. In this case, the control unit 12 may be connectedto the closing device and programmed to drive the closing device to passfrom the first to the second operative condition, should an alarmcondition have been detected. In FIG. 1 the closing device includes thesafety valve 20 (e.g. a solenoid valve) controlled by the control unit12 as described above. Obviously a valve of another nature, either anocclusive pump or a further member configured to selectively prevent andenable fluid passage may be used.

Additionally to the safety valve 20, the closing device comprises abypass line 23 which connects the treatment fluid supply line 8 and theeffluent line 13 bypassing the blood treatment device 2, and one or morefluid check members 24 connected to the control unit 12 for selectivelyopening and closing the bypass line 23. The components (bypass line 23and fluid check members 24), which may be alternative or additional tothe presence of the safety valve 20 are represented by a broken line inFIG. 1 . The check members 24 on command of the control unit 12 closethe fluid passage towards the blood treatment device 2 and connect thesource directly with the effluent line 13 through the bypass line 23.Again with the aim of controlling the fluid passage towards the bloodtreatment device 2, a treatment fluid pump 25 and a dialysate pump 26may be included, located respectively on the treatment fluid supply line8 and on the effluent line 13 and also operatively connected to thecontrol unit 12. A valve 10 is connected to the control unit 12 and isoperatively placed between the preparation device 9 and the inlet port 4a of the fluid chamber 4. An arterial clamp 15 is connected to thecontrol unit 12 and is operatively placed on the blood withdrawal line 6close to the vascular access of the patient P.

The apparatus also comprises an ultrafiltration device to ultrafilterliquid from the blood chamber 3 towards the fluid chamber 4 of the bloodtreatment device 2 and to the effluent line 13. In the embodiment shownin FIG. 1 , the ultrafiltration device may comprise the treatment fluidpump 25 and the dialysate pump 26 connected and controlled by thecontrol unit 12, as will be explained further on.

The apparatus also comprises a treatment fluid preparation device 9which may be of any known type, for example including one or moreconcentrate sources 27, 28 and respective concentrate pumps 29, 30 forthe delivery, as well as at least a conductivity or ion concentrationsensor 35. Of course other kinds of dialysis fluid preparation devices 9might be equivalently used, having a single or further concentratesources and/or a single or more pumps.

The extracorporeal blood treatment apparatus 1 may comprise variousliquid sources (for example one or more water sources 14 from a waternetwork, at least first and second concentrate sources 27, 28, one ormore sources 33 of disinfectant liquids) connected to the main line 40with respective first and second delivery lines 36, 37 and line 38, theapparatus may exhibit, at each delivery line, a respective check member(not all are shown) and, for example, comprising a valve member 31 and34 and/or an occlusive pump.

The preparation device 9 may be any known system configured for on-linepreparing dialysis fluid from water and concentrates (sodium chlorideand/or calcium chloride and/or magnesium chloride and/or potassiumchloride and/or bicarbonate). Through the preparation device 9,concentrates are diluted in water.

The treatment fluid supply line 8 fluidly connects the preparationdevice 9 for preparing treatment fluid to the blood treatment device 2.The preparation device 9 may be, for example, the one described in theU.S. Pat. No. 6,123,847 the content of which is herein incorporated byreference.

As shown, the treatment fluid supply line 8 connects the preparationdevice 9 for preparing treatment fluid to the blood treatment device 2and comprises a main line 40 whose upstream end is intended to beconnected to a source 14 of running water (water network). The valve 10is part of the main line 40 of the hydraulic circuit 100.

Delivery line/s 36/37 is/are connected to this main line 40, the freeend of which delivery line/s is/are intended to be in fluidcommunication (for example immersed) in a container/s 27, 28 for aconcentrated saline solution each containing sodium chloride and/orcalcium chloride and/or magnesium chloride and/or potassium chloride.

First and second concentrate pumps 29, 30 are arranged in the deliverylines 36, 37 in order to allow the metered mixing of water andconcentrated solution in the main line 40. The concentrate pumps 29, 30are driven on the basis of the comparison between 1) a targetconductivity value for the mixture of liquids formed where the main line40 joins the delivery lines 36, 37, and 2) the value of the conductivityof this mixture measured by means of the conductivity sensor 35 arrangedin the main line 40 immediately downstream of the junction between themain line 40 and the delivery lines 36, 37.

Therefore, as mentioned, the treatment fluid comprises dialysis liquidwhich may contain, for example, ions of sodium, calcium, magnesium, andpotassium and the preparation device 9 may be configured to prepare thetreatment fluid on the basis of a comparison between a targetconductivity value and/or set ion concentration and an actualconductivity value and/or actual ion concentration of the dialysis fluidmeasured by the conductivity sensor 35 of the device 9.

Concentrate pump/s (29, 30) work as regulating means which is configuredto regulate the concentration of a specific substance, in particular anionic substance, in the dialysis liquid. Generally it is advantageous tocontrol the sodium concentration of the dialysis fluid.

The treatment fluid supply line 8 forms an extension of the main line 40of the preparation device 9 for preparing treatment fluid. Arranged inthis treatment fluid supply line, in the direction in which the liquidcirculates, there are the first flow meter 41 and the treatment fluidpump 25.

The effluent line 13 may be provided with the dialysate pump 26 and asecond flow meter 42. The first and second flow meters 41, 42 may beused to control (in a known manner) the fluid balance of a patientconnected to the blood circuit 17 during a dialysis session.

A sensor 11 is provided on the effluent line 13, immediately downstreamthe blood treatment device 2, to measure a parameter value of thedialysate in the effluent line. The sensor 11 is a conductivity sensorwhich is configured to detect conductivity values of the dialysatedownstream of the blood treatment device 2. Alternatively (or incombination) sensor 11 may include a concentration sensor configured formeasuring the concentration of at least one substance in the dialysate,such as sodium concentration.

One or more infusion lines 43 may also be included, with respectiveinfusion pumps 44 or flow regulation valves, the infusion lines beingconnected up to the blood return line 7 and/or the blood withdrawal line6 and/or directly to the patient P. The liquid sources for the infusionlines may be pre-packaged bags 45 and/or liquids prepared by theapparatus itself.

In the example of FIG. 1 , an infusion line 43 is shown directlyconnected to the blood return line 7, in particular to the air separator19. The infusion line 43 may either receive infusion liquid from apre-packaged bag 45 (solid line 45 a) or from an online preparationtrough branch 45 b (dotted line).

Of course a pre-infusion line may be alternatively or additionallyprovided receiving the infusion liquid from a bag or from an onlinepreparation device.

The extracorporeal blood treatment apparatus 1 comprises at least onepriming fluid (e.g. saline, in particular saline including asubstantially isotonic liquid with no potassium and magnesium ions)source 50, for example a container like a bag, connected or connectableto the blood withdrawal line 6 upstream of the blood pump 21. A primingfluid delivery line 51, optionally provided with a clamp 53, connectsthe priming fluid source 54 with a point of the blood withdrawal line 6located between the arterial clamp 15 and the blood pump 21, or directlyto the terminal part of the arterial blood line.

In a specific embodiment, the extracorporeal blood treatment apparatuscomprises a further priming fluid (e.g. saline) source 54, for example acontainer like a bag, connected or connectable to either the hydrauliccircuit or to the blood treatment device 2, particularly at the inletport 4 a of the fluid chamber 4.

Given the above description of a possible embodiment of extracorporealblood treatment apparatus, thereafter the specific working of theapparatus is described, as schematically illustrated in the flowchart ofFIG. 10 .

According to the invention, when a patient P reaches the clinic, he hasto wait only the time required to set up and prime the extracorporealblood treatment apparatus 1. Then he is connected to the apparatus 1 tobe submitted to pure ultrafiltration. Time to treatment from the startof the treatment fluid preparation to start the pure ultrafiltration maybe less than 10 min.

At the starting of the apparatus 1, the apparatus 1 is configured, orthe control unit 12 configures the apparatus 1 to be, simultaneously inthe treatment fluid preparation configuration and in the primingconfiguration and thereafter, once priming is ended, the apparatus 1 isswitched to be configured (or the control unit 12 configures theapparatus 1 to be) simultaneously in the treatment fluid preparationconfiguration and in the pure UF configuration.

In particular, the control unit 12 is configured to set the fluidpreparation device 9 to bypass the fluid chamber 4 through the fluidcheck valve 10 (FIG. 1 ) which closes the fluid passage towards theblood treatment device 2 and connects the source directly with theeffluent line 13 through the bypass line 23. FIG. 2 schematically showsthis step (the treatment fluid circuit 32 is illustrated like a box). Ina treatment fluid preparation configuration, the valve 10 is closed toset the fluid flowing in the main line 40 downstream the fluidpreparation device 9 to bypass the fluid chamber 4. No fluid entersthrough the inlet port 4 a of the fluid chamber 4. The patient P is notconnected to the extracorporeal blood circuit 17.

The control unit 12 is configured to receive, e.g. as input from anoperator or from a memory, the set conductivity and/or the set ionconcentration for the treatment fluid and to start injecting at leastone concentrated solution in the main line 40 to increase theconductivity or ion concentration of water flowing in the main line 40.The control unit checks, by means of the conductivity or ionconcentration sensor 35, whether the conductivity or ion concentrationof the fluid flowing in the main line 40 has a proper value fortreatment of patient blood. The proper value is a value within a rangearound the set conductivity and/or the set ion concentration for thetreatment fluid. The range around the set conductivity and/or the setion concentration for the treatment fluid may be less than +/−2 mS/cm,in particular less than +/−1 mS/cm, even more in particular less than0.5 mS/cm. The apparatus 1 continuously raises the conductivity and/orion concentration of the fluid (by continuing injecting into water theconcentrate ion solution) up to obtaining a fluid substantially havingthe set conductivity and/or the set ion concentration.

A temperature sensor 18 is placed in the main line 40 and it isconnected to the control unit 12. The temperature sensor 18 is arrangedto sense the temperature of the treatment fluid downstream a concentratedilution point. The control unit 12 receives, e.g. as input from anoperator or from the memory, a set temperature for the treatment fluidand starts heating water and/or the fluid flowing in the main line 40.In particular, the control unit 12 checks, by means of the temperaturesensor 18, whether the temperature of the fluid flowing in the main line40 has a proper value for treatment of patient blood. The proper valueis a value within a range around the set temperature for the treatmentfluid. The range around the set temperature for the treatment fluid maybe less than +/−2° C., in particular less than +/−1° C., even more inparticular less than 0.5° C. The control unit 12 controls the fluidpreparation device 9, in particular concentrate pumps 29, 30 and valvemembers 31 and 34, to prepare the treatment fluid while the fluidpreparation device 9 bypasses the fluid chamber 4 and is not infused inthe extracorporeal blood circuit. The treatment fluid not having the setconductivity and/or the set ion concentration keeps on flowing throughthe bypass line 23 and into the effluent line 13 until the parameters ofthe treatment fluid, like conductivity and/or ion concentration, arecorrect. The fluid prepared through the treatment fluid preparationdevice 9 and not having the set conductivity and/or the set ionconcentration bypasses the fluid chamber 4 and is not infused in theextracorporeal blood circuit 17.

The fluid preparation device 9 changes the conductivity and/or the ionconcentration of the fluid not having the set conductivity and/or theset ion concentration to prepare the treatment fluid having the setconductivity and/or the set ion concentration.

Meanwhile (FIG. 2 ), the priming fluid source 50 is connected to theblood withdrawal line 6 and the (manual) clamp 53 is open to allow thepriming fluid to flow into the blood withdrawal line 6. In a primingconfiguration and in a first phase, the control unit 12 drives the bloodpump 21 to pump the priming fluid through the blood withdrawal line 6,the blood chamber 3 and the blood return line 7, in order to prime theblood chamber 3 and the blood circuit 17. Safety valve 20 is open andpriming fluid circulates along a normal circulating direction and exitsthe blood return line 7 and then it is evacuated in a drain collectingbag or through the machine drain.

In a first priming with back-filtration embodiment, once priming of theblood chamber 3 is performed and while preparation of the treatmentfluid still runs, the control unit 12 controls the safety valve 20 toclose it. The control unit 12 keeps on driving the blood pump 21 to pumpthe priming fluid through the blood withdrawal line 6 and the bloodchamber 3. Since passage through the blood return line 7 is prevented bythe safety valve 20, priming fluid is pushed across the membrane 5 fromthe blood chamber 3 into the fluid chamber 4 (FIG. 3 ). Priming fluidthan exits from the outlet 4 b of the fluid chamber 4 and into theeffluent line 13. The control unit 12 controls the dialysate pump 26 topump priming fluid into evacuation zone 16. This way, the fluid chamber4 is primed and air may be removed through the drain of the machine or adrain bag. A time interval “ΔT_(pr)” for priming of blood and fluidchambers may be 5 min.

FIGS. 6 and 7 show a different priming sequence, wherein priming theextracorporeal blood circuit 17 includes a first phase of priming theblood withdrawal line 6 and the blood return line 7 and a secondsubsequent phase. In the first phase, the priming fluid source 50 isconnected to the blood return line 7 (FIG. 6 ). The blood pump 21 isactivated to circulate the priming fluid along a reverse circulatingdirection in the extracorporeal blood circuit 17 while keeping thearterial clamp 15 and the safety valve 20 open. The priming fluid isdischarged from the blood withdrawal line 6. In the second phase (FIG. 7), the priming fluid source 50 is connected to the blood withdrawal line6, the arterial clamp 15 is open, the safety valve 20 is closed and theblood pump 21 is activated to circulate the priming fluid in the bloodcircuit along a normal circulating direction, thereby pushing thepriming fluid through the membrane 5 and priming the fluid chamber 4with the priming fluid.

In a further alternative priming procedure, the priming of the bloodcircuit is executed according to the previously described embodiments.An auxiliary priming fluid bag 54 is connected to the dialysis side ofthe circuit (see FIG. 7A). In more detail, the auxiliary priming fluidbag 54 is directly connected to the inlet port 4 a of the bloodtreatment unit 2 by means of an auxiliary priming line. Fluid (e.g.,saline) from the auxiliary priming fluid bag 54 is used to prime thefluid chamber 4. This step may be executed at any time during primingoperations; however, it is generally performed after priming the bloodcircuit. A pump of the apparatus (such as the dialysate pump) withdrawsfluid from the auxiliary priming fluid bag 54 and make it pass throughthe fluid chamber 4 to prime it and remove air/air bubbles. The spentfluid is evacuated via a drain (e.g. the machine drain or a drain bag).This alternative priming method avoids back-filtering through thesemipermeable membrane.

In a further alternative priming procedure (FIG. 7B), the priming fluidsource 50 is connected to the blood return line 7 and the bloodwithdrawal line 6 is directly connected to the inlet port 4 a of thefluid chamber 4 through a tubing (FIG. 7B). The blood pump 21 isactivated to circulate the priming fluid along a reverse circulatingdirection in the extracorporeal blood circuit 17 while keeping thearterial clamp 15 and the safety valve 20 open. The priming fluid flowsthrough the blood chamber 3, out of the inlet port 3 a of the bloodchamber 3 and then into the fluid chamber 4. Priming fluid than exitsfrom the outlet 4 b of the fluid chamber 4 and flows into the effluentline 13.

Once priming of blood chamber and of fluid chamber has been performed,the control unit 12 stops the blood pump 21; the safety valves 15 and 20are closed. While preparation of the treatment fluid still runs and thefluid preparation device 9 still bypasses the fluid chamber 4 and is notinfused in the extracorporeal blood circuit 17, patient P could beconnected to the extracorporeal blood circuit 17.

FIGS. 8A and 8B show how the patient P may be connected. The bloodwithdrawal line 6 and the blood return line 7 are connected to thepatient P while the arterial clamp 15 and the safety valve 20 are stillclosed and an effluent clamp 200 on the effluent line 13 is closed too(FIG. 8A). Then the arterial clamp 15 and the safety valve 20 are openedand the blood pump 21 is activated according to the normal circulatingdirection while the effluent clamp 200 is still closed (FIG. 8B).Priming fluid in the line is progressively substituted by blood.

FIGS. 9 a and 9 b show another way of connecting the patient P. Theblood withdrawal line 6 is connected to the patient P while the bloodreturn line is still connected to the priming fluid source/bag 50. Thearterial clamp 15, the safety valve 20 and an effluent clamp 200 on theeffluent line 13 are closed (FIG. 9A). Then the arterial clamp 15 andthe safety valve 20 are opened while the effluent clamp 200 remainsclosed and the blood pump 21 is activated according to the normalcirculating direction (FIG. 9B). Priming fluid in the line isprogressively substituted by blood and said priming fluid is collectedinto the priming fluid source/bag 50 which works as a waste bag. At theend of this step, the blood return line is connected to the patient P.

The control unit 12 controls the ultrafiltration device 25, 26 toperform pure ultrafiltration of fluid from the extracorporeal blood ofthe patient P (FIG. 4 ). The control unit 12 controls the dialysate pump26 to pump waste fluid into the evacuation zone 16. Waste fluid removedfrom blood and crossing the membrane 5 is evacuated through the effluentline 13.

A time interval “ΔT_(tfp)” for treatment fluid preparation may last 20min. A time interval “ΔT_(puhf)” of the pure ultrafiltration is thedifference between the fluid preparation time interval “ΔT_(tfp)” andthe priming time interval “ΔT_(pr)” and may be 15 min.

When the treatment fluid is ready for treating the patient blood, i.e.the treatment fluid reached the proper parameter values (temperature,conductivity and/or ion concentration), the control unit 12 raises analert for the user, in order to require the dialysate connectors to beboth placed in the right position at the dialyzer, then controls thefluid check members 24 to restore the fluid connection of the watersource 14 and of the treatment fluid preparation device 9 of thetreatment fluid circuit 32 to the inlet port 4 a of the fluid chamber 4and/or to the infusion line 43 for injecting substitution fluid in theblood circuit. In a treatment configuration, the control unit 12controls the treatment fluid pump 25 to pump treatment fluid through thefluid chamber 4 while blood flows in the blood chamber 3 and/or to theinfusion line 43. Hemodialysis treatment (or hemodiafiltration treatmentor hemofiltration treatment) of the patient P could start (FIG. 5 ).

In a different way of working, at the starting of the apparatus 1, theapparatus 1 may be configured (or the control unit 12 configures theapparatus to be) simultaneously in the treatment fluid preparationconfiguration and in the pure UF configuration. In an alternative, afterpriming the blood line circuit and the fluid chamber and during on-linedialysis fluid preparation, one or more fresh dialysis fluid containersmay be connected to the inlet port of the fluid chamber and or to theextracorporeal blood circuit. The control unit could be configured toadditionally run an hemodyalisis (HD) treatment flowing fresh dialysisfluid in the fluid chamber and patient blood in the blood chamber or anhemofiltrtion (HF) treatment injecting fresh dialysis fluid in theextracorporeal blood or and hemodiafiltration (HDF) treatment (combiningHD and HF) simultaneously with the step of controlling the fluidpreparation device to prepare the online dialysis fluid (i.e. change aconductivity and/or an ion concentration of the fluid not having the setconductivity and/or the set ion concentration to prepare the treatmentfluid having the set conductivity and/or the set ion concentration). TheHD, HF or HDF treatment may be delivered after a pure ultrafiltrationinitial treatment or as an alternative to the pure ultrafiltration.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andthe scope of the appended claims.

1. A method for controlling an extracorporeal blood treatment apparatuswith an extracorporeal blood circuit comprising: setting a hydrauliccircuit so that a fluid prepared through a fluid preparation device andnot having a set conductivity and/or a set ion concentration bypasses afluid chamber of a blood treatment device and is not infused in theextracorporeal blood circuit; controlling the fluid preparation deviceto change a conductivity and/or an ion concentration of the fluid nothaving the set conductivity and/or the set ion concentration to preparea treatment fluid having the set conductivity and/or the set ionconcentration while bypassing the fluid chamber and not infusing thefluid in the extracorporeal blood circuit; and simultaneouslycontrolling an ultrafiltration device of the extracorporeal bloodtreatment apparatus to perform pure ultrafiltration of fluid from theextracorporeal blood of a patient connected to a blood withdrawal lineand to a blood return line of the extracorporeal blood circuit.
 2. Themethod according to claim 1, wherein, in a priming configuration, theapparatus comprises at least one priming fluid source of a priming fluidconnected to the extracorporeal blood circuit, to the blood treatmentdevice, or to the hydraulic circuit.
 3. The method according to claim 2,comprising, in the priming configuration, priming the extracorporealblood circuit with the priming fluid before connecting the patient andwhile the fluid preparation device is preparing the treatment fluid, thepriming fluid source connected to the extracorporeal blood circuit. 4.The method according to claim 3, comprising, in the primingconfiguration, priming the fluid chamber and at least part of thehydraulic circuit with the priming fluid by pushing the priming fluidthrough a semipermeable membrane from a blood chamber of theextracorporeal blood circuit into the fluid chamber before connectingthe patient and while the fluid preparation device is preparing thetreatment fluid.
 5. The method according to claim 3, comprising, in thepriming configuration, priming the fluid chamber and at least part ofthe hydraulic circuit with a priming fluid from an auxiliary primingfluid source, the auxiliary priming fluid source connected to the bloodtreatment device or to the hydraulic circuit and separated by asemipermeable membrane from the extracorporeal blood circuit.
 6. Themethod according to claim 1, comprising, in a treatment configuration,connecting the fluid preparation device to the fluid chamber and/or tothe extracorporeal blood circuit when the treatment fluid having the setconductivity and/or the set ion concentration is ready for treating thepatient blood.
 7. The method according to claim 1, comprising, in atreatment configuration, starting a hemodialysis treatment, ahemofiltration treatment, or a hemodiafiltration treatment on thepatient when the treatment fluid having the set conductivity and/or theset ion concentration is ready.
 8. The method according to claim 1,wherein, the hydraulic circuit comprises a main line having a valveoperatively placed between the fluid preparation device and an inletport of the fluid chamber, the method comprising, in a treatment fluidpreparation configuration, closing the valve to set the fluid flowing inthe main line downstream the fluid preparation device to bypass thefluid chamber.
 9. The method according to claim 8, comprising, in atreatment configuration, when the treatment fluid is ready in order tostart a hemodialysis treatment, a hemofiltration treatment, or ahemodiafiltration treatment on the patient, opening the valve to connectthe fluid preparation device to the inlet port of the fluid chamberand/or to an infusion line for injecting substitution fluid in the bloodcircuit.
 10. The method according to claim 2, wherein, in the primingconfiguration, priming the extracorporeal blood circuit includescontrolling a blood pump while the priming fluid source is connected tothe extracorporeal blood circuit to pump the priming fluid in theextracorporeal blood circuit and to prime the extracorporeal bloodcircuit with the priming fluid, wherein, in the priming configurationthe extracorporeal blood circuit is directly connected to the fluidchamber via a tube, and, the blood withdrawal line is directly connectedto the inlet port of the fluid chamber, wherein the blood pumpcirculates the priming fluid along a reverse circulating directionpumping the priming fluid into the fluid chamber through the tube, inorder to prime said fluid chamber and at least part of the hydrauliccircuit, and wherein, in the priming configuration, the priming fluidflows through the blood chamber, out of the inlet port of the bloodchamber, then into the fluid chamber, exits from the outlet of the fluidchamber, and flows into an effluent line.
 11. The method according toclaim 2, wherein, the extracorporeal blood treatment apparatus comprisesa safety valve placed along the blood return line and an arterial clampplaced along the blood withdrawal line, and wherein, in the primingconfiguration, priming the extracorporeal blood circuit includes a firstphase of priming the blood withdrawal line and the blood return lineactivating a blood pump to circulate priming fluid along a reversecirculating direction, in the extracorporeal blood circuit and keepingthe arterial clamp and the safety valve open and a second phase ofclosing the safety valve and activating the blood pump to circulate thepriming fluid in the blood circuit along a normal circulating direction,thereby pushing the priming fluid through a semipermeable membrane andpriming the fluid chamber with the priming fluid.
 12. The Methodaccording to claim 11, wherein, the extracorporeal blood treatmentapparatus comprises a drain in fluid communication with the fluidchamber and the second phase includes removing air from the fluidchamber through the drain.
 13. The method according to claim 1, wherein,the fluid preparation device comprises a conductivity or an ionconcentration sensor placed in a main line arranged to senseconductivity or ion concentration of the treatment fluid downstream aconcentrate dilution point, and wherein in controlling the fluidpreparation device, the method comprises: receiving the set conductivityand/or the set ion concentration for the treatment fluid; begininjecting at least one concentrated solution in the main line toincrease the conductivity or ion concentration of water flowing in themain line; receiving from the conductivity or ion concentration sensor asignal indicative of the conductivity or ion concentration of the fluidflowing in the main line; and checking, by means of the conductivity orion concentration sensor, whether the conductivity or ion concentrationof the fluid flowing in the main line has a proper value for treatmentof the patient's blood, the proper value being a value within a rangearound the set conductivity and/or the set ion concentration for thetreatment fluid.
 14. The method according to claim 1, comprising, incontrolling the fluid preparation device: receiving a set temperaturefor the treatment fluid; begin heating water and/or the fluid flowing ina main line; and checking, by means of a temperature sensor, whether thetemperature of the fluid flowing in the main line has a proper value fortreatment of the patient's blood, the proper value being a value withina range around the set temperature for the treatment fluid.
 15. Themethod according to claim 1, comprising, in a treatment fluidpreparation configuration, setting the hydraulic circuit so that thefluid prepared through the fluid preparation device and not having theset conductivity and/or the set ion concentration bypasses the fluidchamber and is not infused in the extracorporeal blood circuit; andcontrolling the fluid preparation device to change a conductivity and/oran ion concentration of the fluid not having the set conductivity and/orthe set ion concentration to prepare the treatment fluid having the setconductivity and/or the set ion concentration while bypassing the fluidchamber and not infusing the fluid in the extracorporeal blood circuit,wherein controlling the fluid preparation device includes starting toinject at least one concentrate solution in water to raise waterconductivity and/or ion concentration.
 16. The method according to claim1, comprising, in a pure UF configuration, setting the hydraulic circuitso that the fluid prepared through the fluid preparation device bypassesthe fluid chamber and is not infused in the extracorporeal bloodcircuit; and controlling the ultrafiltration device to perform pureultrafiltration of fluid from the extracorporeal blood of the patientconnected to the extracorporeal blood circuit.
 17. The method accordingto claim 16, comprising, at least at the startup of the apparatus,providing: simultaneously both a treatment fluid preparationconfiguration and a priming configuration of the extracorporeal bloodtreatment apparatus; or simultaneously both the treatment fluidpreparation configuration and a pure UF configuration of theextracorporeal blood treatment apparatus.
 18. The method according toclaim 1, wherein the extracorporeal blood treatment apparatus comprises:the blood treatment device including a blood chamber and the fluidchamber separated from each other by a semipermeable membrane; theextracorporeal blood circuit comprising the blood withdrawal lineconnected to an inlet port of the blood chamber and the blood returnline connected to an outlet port of the blood chamber; a blood pumpconfigured to be coupled to the extracorporeal blood circuit tocirculate blood in the extracorporeal blood circuit; the hydrauliccircuit including a main line connectable to an inlet port of the fluidchamber and/or to the extracorporeal blood circuit and an effluent lineconnected to an outlet port of the fluid chamber, the main line beingconnectable to a water network to receive water, wherein the hydrauliccircuit comprises the fluid preparation device configured to diluteconcentrates in water to prepare the treatment fluid having setconductivity and/or set ion concentration; the ultrafiltration deviceconfigured to ultrafilter liquid from the blood chamber towards thefluid chamber of the blood treatment device and to the effluent line;and a control unit connected to the preparation device, to theultrafiltration device and to the blood pump.
 19. A method forcontrolling an extracorporeal blood treatment apparatus with anextracorporeal blood circuit comprising: setting a hydraulic circuit sothat a fluid prepared through a fluid preparation device and not havinga set conductivity and/or a set ion concentration bypasses a fluidchamber of a blood treatment device and is not infused in theextracorporeal blood circuit; controlling the fluid preparation deviceto change a conductivity and/or an ion concentration of the fluid nothaving the set conductivity and/or the set ion concentration to preparea treatment fluid having the set conductivity and/or the set ionconcentration while bypassing the fluid chamber and not infusing thefluid in the extracorporeal blood circuit; and simultaneously, in apriming configuration, priming the extracorporeal blood circuit with apriming fluid before connecting a patient and while the fluidpreparation device is preparing the treatment fluid.
 20. The methodaccording to claim 19, wherein the fluid preparation device comprises aconductivity or a ion concentration sensor placed in a main line of thehydraulic circuit and arranged to sense conductivity or ionconcentration of the treatment fluid downstream a concentrate dilutionpoint, wherein, during controlling the fluid preparation device, themethod comprises: receiving the set conductivity and/or the set ionconcentration for the treatment fluid; begin injecting at least oneconcentrated solution in the main line to increase the conductivity orion concentration of water flowing in the main line; receiving from theconductivity or ion concentration sensor a signal indicative of theconductivity or ion concentration of the fluid flowing in the main line;and checking, by means of the conductivity or ion concentration sensor,whether the conductivity or ion concentration of the fluid flowing inthe main line has a proper value for treatment of the patient's blood,the proper value being a value within a range around the setconductivity and/or the set ion concentration for the treatment fluid.